Clinical Core (Core A) is responsible for centralized functions that provide the foundation for the proposed research in this Program Project. The 4 functions of the Core are (1) to provide access to patients with ANCA disease throughout their disease course for recruitment into the proposed studies, (2) to collect, process and store biologic samples from patients at various disease stages as well as from family members and controls, (3) monitor and manage information on the long-term outcomes in patients with ANCA disease using standard definitions, and, (4) manage, integrate and process the medical and biologic information from components of all projects, which includes management of the integrated database, and statistical analyses and interpretation of results. Careful clinical characterization and long-term follow-up of patients with ANCA disease is a major effort that requires an experienced team of investigators and staff as put together by this Core. The Core provides uniform identification of remission and relapses of the disease, which facilitates the coordination of biologic sample collections during these different disease stages. Identification of patients with various levels of disease activity is also critical for determination of those eligible for proposed trials and clinical studies. The collection of biologic samples from family members of patients with ANCA disease and healthy controls can also be accomplished as required by Core A. Core A has well established methods for the collection of samples in conjunction with a database system for storage and identification of multiple samples among patients. The database allows for the unique information required for each study to be easily linked with clinical information. Core A will also provide support needed for study design and statistical analyses throughout the proposed program project, with the goal of assisting all projects in the successful and timely publication of results. This Core has been in existence under the leadership of Susan L. Hogan, PhD since the original cycle of funding for this Program Project in 1999. The overall experience and dedication of the faculty and staff of Core A will continue to bring a strong resource on which each project can depend and can, therefore, successfully launch their laudable scientific goals.